Elisabeth S. Vrba is professor of geology and geophysics at Yale University. She is also coeditor of Paleoclimate and Evolution, with Emphasis on Human Origins, published by Yale University Press. George B. Schaller is a conservation biologist at the Wildlife Conservation Society and author of many well-known books, including The Last Panda, Tibet's Hidden Wilderness, and The Year of the Gorilla.
This volume is sponsored by the Yale Institute for Biospheric Studies and the Wildlife Conservation Society, New York.